C#

<br />
//get HDC of the image in the box<br />
Image img = picturebox.Image;<br />
Graphics graphics = Graphics.FromImage(img);<br />
IntPtr hdc = graphics.GetHdc();<br />
<br />
//call VC++ function to paint the image<br />
//...<br />
<br />
//release HDC and Graphics<br />
graphics.ReleaseHdc(hdc);<br />
graphics.Dispose();<br />
<br />
//show the image<br />
picturebox.Refresh();<br />

<br />
//createn empty image<br />
picturebox.Image = new Bitmap(width, height);<br />

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private void button1_Click(object sender, System.EventArgs e)
{
	this.richTextBox1.Focus();
	SendKeys.Send("{BACKSPACE}");
}

using System.Windows.Forms;

private void button1_Click(object sender, EventArgs e)
{
this.richTextBox1.Text = this.richTextBox1.Text.Remove(this.richTextBox1.TextLength - 1, 1);
}